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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using an isolated rat heart preparation (Langendorff perfusion, perfusion pressure 100 cm H2O) the response of the hypertrophied heart (spontaneous hypertensive rats lv/bw ratio 3.6 +/- 0.5) to global normothermic (30 min) and hypothermic (25 degrees C, 120 min) ischemic and cardioplegic arrest and reperfusion (30 min) was examined and compared with normal hearts (Wistar rats lv/bw ratio 2.0 +/- 0.3). St. Thomas solution and verapamil (2 mg/l Ringer solution) were used as cardioplegic agents. Before ischemia hypertrophied hearts had a significantly higher pressure-rate product, a lower myocardial perfusion/g myocardium and a lower myocardial ATP and adenine nucleotide content. Unmodified ischemia reduced myocardial function in the hypertrophied hearts to a greater degree than in normal hearts in both normo- and hypothermia. St. Thomas solution and verapamil protected significantly the myocardial function in the normal and hypertrophied heart after normothermic ischemia in a similar manner (60-70% of the initial value). In the hypertrophied ventricle ATP decay and adenine nucleotide loss was greater in verapamil than in St. Thomas solution treated hearts. In hypothermic ischemia only St. Thomas solution protected left ventricular function and adenine nucleotide loss in both normal and hypertrophied hearts. Verapamil was ineffective in the normal ventricle and protected left ventricular function but not the ATP and adenine nucleotide decay in the hypertrophied heart.
Basic Res Cardiol 1986
PMID:Function and energy-rich phosphate content of the hypertrophied ventricle after global ischemia and reperfusion. 294 60

The authors relate their experience concerning the surgical correction of congenital coronary fistula. Between May 1971 and June 1986, 9 patients (4 boys and 5 girls) aged from 17 days to 49 years were operated upon at the Division of Cardiac Surgery of Bergamo (Ospedali Riuniti). All the patients, except three who were asymptomatic, showed early cardiac failure or dyspnoea on effort and angina in the elderly. At the physical examination a continuous murmur was heard in 8 cases; the chest x-ray showed significant cardiomegaly and on the electrocardiogram a right/left ventricular hypertrophy pattern was detected in 5 patients. All the patients underwent cardiac catheterization and a coronary angiography. The left-to-right shunt ranged from 60% to 250% of the cardiac output. The anomalous communication affected the right coronary artery in 7 cases and the left in 2, opening into the right atrium in 4 patients, into the right ventricle in 3 and into the pulmonary artery in 2. All patients but one, in whom division and suture were the only necessary procedures, underwent correction by means conventional cardiopulmonary by-pass with moderate hypothermia. In 3 cases closure through the coronary artery was preferred, in 1 through the right ventricle and in 2 transpulmonary. There was only 1 late death which occurred in a 3 year-old patient due to renal failure. After a mean follow-up of 6 years, 7 patients are to be asymptomatic while 1 patient had to be reoperated for a significant residual shunt.
G Ital Cardiol 1988 Feb
PMID:[Congenital coronary fistulae. Comments on 9 surgical cases]. 297 Apr 13

GABA, delta-aminovaleric acid (DAVA) and sodium valproate (VPA) decrease core temperature in conscious rats. Bicuculline increases GABA-induced hypothermia, does not modify DAVA (250 mg/kg) and VPA (100 and 400 mg/kg) hypothermia and antagonizes initial hypothermia by DAVA (1000 mg/kg) and VPA (200 mg/kg) and late hypothermia by DAVA (500 mg/kg) and VPA (200 mg/kg). Picrotoxin increases late hypothermia by GABA (250 mg/kg) and VPA (400 mg/kg), but decreases initial hypothermia by VPA (200 mg/kg). Pentylenetetrazol increases variably GABA-induced hypothermia, inhibits early early hypothermia by DAVA and increases hypothermia induced by VPA (400 mg/kg). We conclude that GABA and GABA-agonists (DAVA and VPA) may induce hypothermia partly mediated by activation of bicuculline-insensitive GABA-receptors.
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PMID:Involvement of bicuculline-insensitive receptors in the hypothermic effect of GABA and its agonists. 299 72

The effect of captopril on energy-rich phosphates and pH during normothermic ischemic arrest, hypothermic cardioplegic arrest and subsequent reperfusion was investigated in the isolated rat heart using 31P-nuclear magnetic resonance. The hearts remained in the probe during all perfusion procedures and captopril (80 ml.l-1) treatment was started directly after cannulation. After normothermic ischemic arrest (15 min), the ATP content of captopril-treated hearts was not significantly different from that of untreated hearts (53 +/- 9% and 52 +/- 8%, respectively). Accumulation of inorganic phosphate at the end of ischemia was significantly less in treated hearts, suggesting a higher end-ischemic nucleotide content in treated hearts. Hypothermic cardioplegic arrest (St. Thomas' Hospital solution, 4 degrees C) lasted for 3 h at 10 degrees C. Adenosine triphosphate in untreated hearts was significantly lower at the end of ischemia; 36 +/- 6% compared to 53 +/- 9% for untreated hearts. Adenosine triphosphate in untreated hearts recovered to 76 +/- 9% after normothermic ischemia and to 72 +/- 7% after hypothermic ischemia at the end of 30 min reperfusion. Captopril significantly improved adenosine triphosphate recovery in both treated groups; 89 +/- 4% after normothermic and 83 +/- 4% hypothermic ischemia. We conclude that captopril has a beneficial effect on recovery of adenosine triphosphate both after normothermic and after hypothermic ischemia.
Basic Res Cardiol
PMID:Captopril improves recovery of adenosine triphosphate during reperfusion of the ischemic isolated rat heart; a 31-phosphorus-nuclear magnetic resonance study. 306 91

Effects of moderate spontaneous hypothermia on left ventricular systolic and diastolic function during acute myocardial infarction were documented in 17 anesthetized dogs with micromanometric pressure and ventriculographic dimension recordings acquired at baseline and at 1 and 3 h after coronary occlusion. In Group 1 (n = 5), core temperature was allowed to decline spontaneously. In Groups 2 (n = 6) and 3 (n = 6), core temperature was maintained at normothermic levels. Hypothermia impaired isovolumic relaxation markedly despite its lack of effect on ventricular volumes or ejection fraction. At 32.3 degrees C, tau 1/2, defined as the time needed for the left ventricular pressure at the time of peak negative rate of change of left ventricular pressure (dP/dt) to fall by 50%, was increased by 129% 3 h after occlusion. In addition, at this temperature significant changes were found in heart rate, cardiac output, minute work, peak positive and peak negative dP/dt, systolic ejection time, mean velocity of circumferential fiber shortening, mean aortic pressure and end-diastolic pressure. Thus, hypothermia evolving under conditions of general anesthesia profoundly alters left ventricular function in the setting of acute myocardial infarction, a phenomenon that requires consideration and control in studies of myocardial ischemia and left ventricular function in experimental animals.
J Am Coll Cardiol 1988 Jan
PMID:Sensitivity of isovolumic relaxation to hypothermia during myocardial infarction. 333 99

Eighty-three patients underwent surgical correction of total anomalous pulmonary venous connection (TAPVC) between 1973 and 1986. There were 46 boys and 37 girls. Median age at operation was 60 days (1 to 240) and median weight 3.9 kg (1 to 22). The anatomic types encountered included infracardiac connection (16 patients), supracardiac connection (32) and pulmonary venous drainage connected directly to the coronary sinus (27). Mixed anomalous drainage or pulmonary venous return connected directly to the right atrium occurred in 8 patients. Diagnosis was established by cardiac catheterization and angiography (56 patients), clinical examination (3) and cross-sectional echocardiography alone in 24 of the last consecutive 28 patients. Pulmonary hypertension was present in 26 (55%) of those who underwent cardiac catheterization. The median pulmonary vascular resistance was 4.2 units/m2 (body surface area) for all the patients, whereas in those with infracardiac pulmonary venous connection the median value was 10 units/m2. The median interval between admission and operation was 72 hours. Surgical correction was performed using profound hypothermia and circulatory arrest in 68; for the remainder, conventional cardiopulmonary bypass with profound to moderate hypothermia was used. Ten patients developed 1 or more pulmonary hypertensive crises during the early postoperative period. These were diagnosed in 8 by direct pulmonary artery pressure measurement and in 2 by clinical examination. Late reoperation was necessary in 6 patients (10%). Analyses of risk factors for 30-day survival for all patients showed that the risk of early death was associated with the type of anomaly (infradiaphragmatic), occurrence of pulmonary hypertensive crises, year of the operation, set of the patient and pressure of preoperative congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Cardiol 1988 Mar 01
PMID:Surgical risk factors in total anomalous pulmonary venous connection. 334 86

Hypothermia is known to affect the electrophysiology of the myocardium in various ways. A marked increase in action potential duration, combined with a decrease in rate of depolarization and conduction velocity, has been observed. We studied the effect of localized hypothermia of the ventricular myocardium on the high-frequency (HF) components of the ECG waveform. Signals were obtained from 6 anesthetized dogs using simultaneous recording of three orthogonal body surface leads before, during, and following surface cooling of different areas of the epicardium. Computer analysis included digital averaging and filtering in a frequency range of 150-250 Hz. For each intervention in each animal, the variance of the average nonfiltered QRS complex was used for a quantitative estimate of the total power, whereas the variance of the derived filtered wave (HF QRS complex) expressed the power content in the HF range. The total power increased during localized cooling of the anterior as well as the inferior epicardial surface, while a clear reduction of power was observed in the HF range. This reduction was shown to be lead dependent and nonuniformly distributed during the course of the QRS. In all cases, hypothermia of either anterior or inferior ventricular epicardium produced a zone of reduced amplitude in the HF QRS complex of at least one lead. Thus, typical changes in the morphology of the HF QRS complex are reliable markers for cooling-induced localized electrophysiological (EP) variations. Therefore, the HF analysis of the body surface ECG may provide noninvasive insight into the EP properties of the myocardium.
Clin Cardiol 1988 Feb
PMID:Effect of localized surface cooling of the heart muscle on the high-frequency content of ECG waveforms in dogs. 334 5

A one-month-old infant developed atypical ventricular tachycardia, complete right bundle branch black, and alternating 2:1 Osborn waves during spontaneous mild hypothermia; 10 h after rewarming, the electrocardiogram was normal.
Pediatr Cardiol 1988
PMID:Atypical ventricular tachycardia and alternating Osborn waves induced by spontaneous mild hypothermia. 334 93

Although many studies of the protective effects of cardioplegic solutions using hypothermia have been conducted, it is also necessary to examine their protective effects under normothermia as regional increases in myocardial temperature during hypothermic arrest are often reported. For this purpose myocardial protection was investigated in the isolated perfused rabbit heart exposed to 60 minutes of normothermic global ischemia during which Krebs-Henseleit, blood with heparin, Tyers', and St. Thomas' Hospital solutions were infused at 0.2 mL/min. Percent functional recovery dP/dtmax (mm hg/sec) at 5 minutes relative to pre-ischemic values using Tyers' (12 +/- 5)% was significantly less (p less than 0.05) than recovery using Krebs-Henseleit (57 +/- 13)% and St. Thomas' Hospital solution (47 +/- 5)%. Recovery using blood (79 +/- 7)% was significantly better than all other solutions. Following 25 minutes reperfusion, 4/6 hearts perfused with Tyers' experienced left ventricular fibrillation, while recovery of developed pressure with Krebs-Henseleit (74 +/- 5.8)%, St. Thomas' Hospital (66 +/- 3.4)% and blood (98 +/- 2.9)% was again significantly improved relative to Tyers', (p less than 0.05). Time to develop 5 mm contracture during the ischemic period was significantly shorter using Tyers' than with the other solutions. Using these indices of function, whereas Tyers' solution provided poor protection, blood provided excellent protection in rabbit hearts under normothermic conditions.
Can J Cardiol 1987 Apr
PMID:Myocardial protection during ischemia in the isolated perfused rabbit heart. 359 93

The management of three infants born with a combination of tetralogy of Fallot and a vascular ring causing tracheoesophageal compression is described. There was a double aortic arch in two patients and an aberrant left subclavian artery with left ligamentum arteriosum and right aortic arch in one. Single-stage corrective surgery of both lesions during infancy, performed under profound hypothermia and circulatory arrest, was successful. In our opinion, this is the treatment of choice, when the anatomy of the tetralogy is favorable for primary correction.
Pediatr Cardiol 1987
PMID:Surgical management in tetralogy of Fallot and vascular ring. 362 69


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